TOPSwitch 261EN-High peak between pins D-S
Hello,
I would like to built battery charger for LiFePO4 with output 11V and 16A.
I have choosen TOPSwitch-HX 261EN(eSIP-7C), 132Khz, secondary TL431, single 230 V.
For now I have tried with low AC voltage 120 V, because voltage on Mosfet(between pins D-S) it has very high peak
with 120V AC it has peak around 650 V.
Can you check my schema what is wrong?
Schema is in the supplement.
Thank you for answers.
评论
Leakage inductance is 12,36 uH. Snubber resistors are all right. I will try to remove resistor.
Do you make those test with a load?
I'm not an expert in this topic so take my comment with tweezers; I think that, if you make those test with no load, may be the energy, stored in the ferrite core, is getting back to the TOPSwitch.
Yes, i made this test with load. Load was two small bulbs 25W in series.
What is leakage inductance of your transformer? Perhaps try removing 6.8 ohm in series with snubber diode. Also measure peak drain current. Are you sure snubber bleeder resistors are intact? -- perhaps it is clmaping only by zener.